The Durable and Soft Fabric You Didn’t Know You Loved!

When it comes to choosing the perfect fabric for comfort, durability, and versatility, interlock knit often flies under the radar—yet it deserves the spotlight. Whether you’re a fashion designer, a DIY sewist, or simply someone who appreciates a well-made t-shirt, understanding what interlock knit is and why it’s so special can elevate your fabric game.

What Is Interlock Knit?
Interlock knit is a type of double-knit fabric, meaning it’s made on a knitting machine with two needle beds. Unlike single-knit fabrics (like jersey), interlock is constructed with two rows of stitches that interlock—hence the name. This construction results in a fabric that’s thicker, more stable, and smoother on both sides compared to its single-knit counterparts. These features make interlock knit a dream to sew with, even for beginners.

Key Characteristics of Interlock Knit
Here’s what makes interlock knit stand out:
- Softness: It’s incredibly smooth and soft to the touch, which makes it ideal for clothing worn close to the skin—think baby clothes, underwear, and t-shirts.
- Thickness: The double-knit nature means it’s generally thicker than jersey, offering more warmth and opacity.
- Stability: Interlock doesn’t curl at the edges when cut, unlike jersey, making it easier to sew—especially for beginners.
- Stretch & Recovery: It has a natural stretch (especially crosswise) and decent recovery, making it comfortable for garments that move with the body.
- Reversible: With the same appearance on both sides, interlock gives more flexibility in design and usage.


Interlock knit is incredibly versatile. You’ll often find it in:
- Baby/Kid clothes (like the bodysuits and playsuits we sell by Kinder Birch which are great for Baby showers, like the Solid Cream bodysuits for decorating!)
- Loungewear (check out Birch’s Yoga Pants Tutorial)
- T-shirts (here’s a cute, basic tank tutorial)
- Dresses (like the Perfect Summer Swing Dress)
- Lightweight sweaters (see the Rohan Hoodie)
Its combination of comfort and structure makes it perfect for garments that need both shape and softness.


Sewing Tips for Interlock Knit
- Use a ballpoint or stretch needle to avoid snags.
- A walking foot helps layers feed evenly.
- Finish seams with a serger, or use a zigzag or stretch stitch on your sewing machine.
- Avoid over-stretching the fabric while sewing to prevent puckering.
Caring for Interlock Knit
Birch Fabrics’ interlock knits are made from 95% cotton, 5% spandex making them easy to care for. Machine wash cold and tumble dry low to preserve the fabric’s softness and elasticity.
Final Thoughts
Interlock knit offers a perfect balance between comfort and structure. It’s a workhorse in the knit fabric world—understated yet indispensable. Whether you’re crafting children’s clothes or designing a cozy fall collection, interlock is a fabric worth exploring.
So next time you run your hand over a super-soft t-shirt or admire a garment that holds its shape beautifully, there’s a good chance it’s made from interlock knit—and now you know why it feels just right.